The invention relates to a data-input device comprising a designator able to point to a position on a screen of a computer system to which the device is connected.
To date, the designator used most often is a mouse of which the position on a flat surface allows an operator to point at a position on a screen of the computer system. Numerous other designators are also used, such as a touch-sensitive pad (or touchpad) fixed near a keyboard of the system, a mini stick (or joystick) or a designator ball (or track ball).
Designators may be grouped into two broad families; those having a fixed part such as the touchpad, the joystick and the track ball, and those which do not have a fixed part, such as the mouse.
A designator allows various positions to be pointed at on the screen. In order to move between two positions, the operator moves a mobile part of the designator or moves his finger in the case of a touchpad. The movement is measured in an orthogonal frame of reference that the computer system matches up with a frame of reference of the screen.
In order to improve the ergonomics of designators, a support surface may be provided, its purpose being to support the hand of the operator as he manipulates the designator. This surface makes it possible to limit tension in the operator's wrist. In the case of a mouse, the support surface is formed directly by the shape of the mouse on which the operator rests the palm of his hand. In the case of the family of designators having a fixed part, a palm rest that forms an integral part of the fixed part of the designator may be provided. The palm rest has a shape, for example that of a portion of a sphere, that conforms to the interior surface of the palm of the hand.
Various knobs or buttons allowing data acquisition, such as, for example, a push-button which for example allows validation of a value to which the designator is pointing may be associated with the designator. In the case of the family of designators having a fixed part, this type of push-button is generally situated on one side of the palm rest. This button is manipulated using the operator's thumb.
Near to the designator there may be double-ring rotary knobs that notably allow coarse adjustment of the value of a data item in the case of one of the rings and fine adjustment of the same value in the case of the other ring. In order to validate the value adopted, the validation button of the designator can be used. The distance separating the rotary knob from the validation button forces the operator to move his hand between a position for selecting the value on the rotary knob and a position for validating on the side of the palm rest. More specifically, the rotary knob is generally manipulated between the thumb and index finger. The thumb then has to be moved in order to reach the validation button.
More generally, recent computer systems demand a great many access ways for selecting and validating various data items. These access ways entail numerous manipulations on the part of the operator. These manipulations involve moving his hand to switch from one data input means to another. These movements are ergonomically delicate. First of all, the fact of moving the hand from one button or knob to another is a source of error. Next, the movements require a significant amount of learning and even if the operator performs the movements quickly, a minimum amount of time is needed to switch from one button or knob to another.